Q: Woobing noise, change as the speed changes

This is almost certainly tire-related. The fact that the sound correlates to the speed is a dead giveaway. The only other sound that correlates to speed like you describe would be like a rubbing brake pad or something, but that would be a metallic sound and not a "woob". I am a little suspicious of a the shop however. If the tires are balanced, in good mechanical shape, and all the tires are aligned, you shouldn’t be hearing any noise like that. The fact that you only replaced 2 tires is making me lean towards guessing one of the other 2 tires are out of balance.

If you can feel a wobble in the steering wheel, then at least one of the front tires are out of balance. If there is no wobble in the steering wheel, it could still be one of the back tires. If you want to test it yourself, rotate the tires in an X pattern, bringing the rear tires to the front and drive it, checking for a wobbling steering wheel. If that still doesn’t answer the problem, take it to a different shop. Don’t tell them about your experience at the other shop, just explain the problem and see what they say. Alternatively, a certified technician from YourMechanic can come to your car’s location to inspect the noise and advise you on the correct fix.